The present invention relates to the feeding of rivets or other fasteners or similar articles to riveting or other fastener inserting means.
In riveting machines the rivet blanks having heads at one end of each are commonly fed to the riveting apparatus by passing them downwardly through a feed tube and thence laterally to rivet receiving fingers which support the same and insert them through holes in workpieces to be riveted. Passage of the rivet blanks downwardly through the feed tube may be by gravity alone or by air pressure against rivet blanks downwardly through the feed tube.
The present invention provides means to prevent cocking of rivet blanks in the feed tube which interferes with feeding thereof and also makes it possible to employ the rivet feeding mechanism in any orientation, including an upside-down orientation with respect to conventional downwardly moving rivet blanks.
In U.S. Pat. No. 3,647,129 to Ehrlich, air pressure is employed to direct successive rivet blanks laterally from the feed tube into a rivet receiving channel extending at right angles to the feed tube.
In U.S. Pat. No. 3,906,615 to Campbell, Jr. et al, the rivet blanks are free to cock as they move along the feed tube but are ultimately straightened by movement into engagement with an O-ring at the discharge end of the feed tube, if, in fact, they ultimately reach such discharge end.
In U.S. Pat. No. 3,946,926 to Willis, as best shown in FIG. 6 thereof, air is permitted to bleed off from beneath the fasteners to permit their free downward flow. The individual fasteners are introduced into the feed channel by way of an inlet passage 62 which intersects the feed channel and are moved upwardly by air pressure from such passage to a position where they abut the rivet driving device.
In U.S. Pat. No. 4,194,665, air pressure is merely employed to actuate the staple driving element which is in the form of a pneumatic hammer.
None of the patents referred to above or known to the applicant or his attorney approach the construction shown and claimed herein or provide air pressure means for maintaining rivet blanks against cocking during their passage to the riveting means through a feed tube.